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Direct and indirect ion selective electrodes (ISEs) are two methods commonly used in biochemistry laboratories in order to measure the electrolytes such as sodium. In the clinical practice, it's the sodium concentration in plasma water -measured by direct ISE- which is important to consider as it is responsible of water movements between the liquid compartments. Knowing the difference between the two methods is important because there are situations leading to conflicting results between direct and indirect ISE, especially with sodium and inappropriate therapeutic decisions could be taken if the clinician is not aware of this difference. The increase and the decrease in plasma water volume are the situations that distort the results of the indirect ISE because this method, after a dilution step, does not take into account the real percentage of plasma water of the patient in the determination of the concentrations (leading for sodium to pseudohyponatremia, pseudonormonatremia or pseudohypernatremia). In the direct ISE, the sample is not diluted and the results are correct even if the volume of plasma water is modified. This article specifies the differences between the two techniques through a case of Waldenström's macroglobulinemia and proposes a course of action to follow for both of the biologist and the clinician. © 2015, John Libbey Eurotext. All rights reserved. Source

Gouri A.,Laboratoire Of Biochimie Medicale | Dekaken A.,Service de Medecine Interne
Annales de Biologie Clinique

Aberrations in calcium homeostasis are common observed in patients with chronic renal failure. Measure of total calcium does not reflect the real variation of the calcium status. The proper method to evaluate this issue in hemodialysis patients has not been completely defined. This study aimed to compare the corrected serum calcium levels to ionized calcium levels in hemodialysis patients. Thirty one patients on chronic haemodialysis admitted at the hemodialysis department were retrospectively reviewed. Calcium status was evaluated by measure of ionized levels and as a function of serum calcium levels corrected for albumin aberrations. Based on the measurement of ionized calcium and total calcium corrected, patients were classified into three categories: hypocalcemic, normocalcemic and hypercalcemic. Our result showed that the corrected serum calcium values failed to accurately classify calcium status in 41% of cases. The sensitivity and specificity of the corrected serum calcium formula to evaluate hypocalcemia were 53% and 85%, respectively. Corrected serum values underestimated the prevalence of hypocalcemia and overestimated the prevalence of normocalcemia. In total, the results obtained allow to conclude the lack of interest in the use of correction formulas. Calcium homeostasis should be evaluated by ionized calcium levels rather than as a function of serum calcium and albumin. Source

Watine J.,Laboratoire Of Biologie Polyvalente | Watine J.,Paris Observatory | Wils J.,Paris Observatory | Wils J.,University of Rouen | And 2 more authors.
Journal of Clinical Epidemiology

Objective To challenge the Grading of Recommendations Assessment, Development and Evaluation (GRADE) group to address the potential misconceptions about their approach to grading the strength of recommendations in clinical practice guidelines. Study Design and Setting Based on our own expertise of health care professionals trying to think in depth about, and using, guidelines, we have identified four such misconceptions. Results These potential misconceptions are: (1) evidence in medicine means factual or scientific evidence; (2) opinions are a subcategory of evidence; (3) the most important evidence is related to clinical benefits and harms; (4) being virtuous, and principled, does not particularly help in developing the best possible guidelines. Conclusion We call on the GRADE leadership to address all the above-mentioned misconceptions. These need explicit answers in their manuscript series. © 2014 Elsevier Inc. All rights reserved. Source

Ziegler F.,University of Rouen | Ziegler F.,Laboratoire Of Biochimie Medicale | Tamion F.,University of Rouen | Dechelotte P.,University of Rouen

The main features of semi-elemental enteral diets consist in their specific nitrogen fraction, made of a protein hydrolysate containing di- and tripeptides, which represent the main forms of nitrogen absorption by gastrointestinal tract. Indications focus on acute situations of malnutrition accompanied by reduced capacities of digestion and absorption. Many experimental studies support the interest of semielemental diets. However, clinical studies have been conducted mostly on small groups of patients (single centre studies in the intensive care unit) and have compared semi-elemental diets with polymeric diets, which differ most often not only by the molecular form of nitrogen supply, but also by the amino acid profile, nitrogen concentration, and other nutrients profiles (e.g. lipids, vitamins). Studies with formulas containing almost di-and tripeptides reported no metabolic benefits, because of fast kinetics regarding amino acids absorption,leading to a dramatic increase in liver oxidation, without beneficial effect on protein synthesis. This issue resulted in the development of semi-elemental enteral formula with different peptide profiles, allowing oral use (better palatability) and a drop in manufacturing costs. These formulae improve some parameters of the protein balance. However, clinical use of semi-elemental formula remains limited, in relation to the absence of documented benefits on clinical outcome including morbidity, mortality, and length of hospital stay, also because recent clinical studies are scarce. Currently accepted indications for semi-elemental diets in intensive care patients include post-operative nutritional support after digestive surgery (mainly after small bowel resection), acute pancreatitis, and adaptive phase of intestinal transplantation. Semi-elemental formula may also be used in other patients as second-line diets in case of documented intolerance to polymeric formula. © SRLF et Springer-Verlag France 2011. Source

Duvillard L.,University of Burgundy | Duvillard L.,Laboratoire Of Biochimie Medicale | Florentin E.,University of Burgundy | Florentin E.,Laboratoire Of Biochimie Medicale | And 5 more authors.
Arteriosclerosis, Thrombosis, and Vascular Biology

OBJECTIVE - : In vitro studies showed that insulin stimulates the production of apolipoprotein AI (apoAI). Thus, we hypothesized that chronic hyperinsulinemia could contribute to the increase in the production of high-density lipoprotein apoAI that is observed in metabolic syndrome. APPROACH AND RESULTS - : We performed an in vivo kinetic study with stable isotope in 7 patients with insulinoma who showed hyperinsulinemia but no insulin resistance, 8 patients with insulin resistance, and 16 controls. Insulinemia was 3.1× (P<0.01) higher in patients with insulinoma or insulin resistance than in controls in the fasting state and, respectively, 3.5× and 2.6× (P<0.05) higher in the fed state. The high-density lipoprotein apoAI pool size was smaller in patients with insulin resistance than in controls (49.3±5.4 versus 59.6±7.7 mg·kg; P<0.01), whereas both the high-density lipoprotein apoAI fractional catabolic rate and the high-density lipoprotein apoAI production rate were higher (0.30±0.07 versus 0.20±0.04 pool·d; P<0.0001 and 14.6±1.5 versus 11.5±1.9 mg·kg·d; P<0.01, respectively). In contrast, no significant difference was observed for these parameters between patients with insulinoma and controls. In patients with insulinoma, the apoAI pool size tended to be greater than in patients with insulin resistance (56.3±8.6 versus 49.3±5.4 mg·kg; P=0.078), whereas both the apoAI fractional catabolic rate and the production rate were lower (0.20±0.06 versus 0.30±0.07 pool·d; P<0.01 and 11.1±1.6 versus 14.6±1.5 mg·kg·d; P<0.01, respectively). The apoAI fractional catabolic rate was the only variable associated with the apoAI production rate in multivariate analysis and explained 80% of its variance. CONCLUSIONS - : Chronic endogenous hyperinsulinemia does not induce any increase in the apoAI production rate, which seems to be more dependent on the apoAI fractional catabolic rate. © 2013 American Heart Association, Inc. Source

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